Continuous process for treating wool with chlorocyanurate



July 28, 1970 R. N. BARBER ErAL 3,521,997

CONTINUOUS PRQCESS FOR TREATING WOOL WITH CHLOROCYANURATE Filed April 7, 1967 INV'ENTOR RONALD NORMAN BARBER JAMES EDWARD MADDEN B JZQ United States Patent 3,521,997 CONTINUOUS PROCESS FOR TREATING WOOL WITH CHLOROCYANURATE Ronald N. Barber, Bingley, and James E. Madden, Baildon, England, assignors to I.W.S. Nominee Company Limited, London, England Filed Apr. 7, 1967, Ser. No. 629,321 Claims priority, application Great Britain, Apr. 15, 1966, 16,742/66; Sept. 6, 1966, 39,835/66 Int. Cl. D06m 3/02, 13/34 U.S. Cl. 8127.6 6 Claims ABSTRACT OF THE DISCLOSURE This invention relates to a method of treating wool fibres with salts of chlorocyanuric acids to improve their resistance to shrinking.

Wool fibres are apt to shrink when brought into contact with water, especially when the fibres, or articles made from them, are washed mechanically. It has been proposed to increase the resistance of wool fibres to shrinking by treating them with a dilute solution of an alkali metal salt of a chlorocyanuric acid. A measure of success has been achieved in this way, but these processes have a number of important practical disadvantages. Some of the processes require much equipment, others are very slow and cannot be used for continuous treatments, which are essential if large quantities of material are to be processed cheaply and conveniently. Yet other processes operate under conditions which raise severe corrosion problems. Other disadvantages include discoloration of the wool, with consequent problems in dyeing, damage to the fibres, with reduced tensile strength of yarns and fabrics, and harsh handle of the treated fibres. The successful application of chlorocyanuric acids or their salts therefore involves not only conferring on the wool fibres a satisfactory degree of shrink resistance but also achieving this under conditions which are practical and which result in a treated material having physical characteristics which, with the exception of shrink resistance, conform as closely as possible to those of untreated wool.

It has now been discovered that, by the selection of carefully controlled conditions, wool fibres can be successfully treated in a continuous fashion to give an entirely acceptable degree of shrink resistance accompanied by desirable properties in other respects.

According to this invention, wool fibres are continuously treated by a process which comprises passing the fibres into an impregnation zone wherein the fibres are impregnated with an aqueous solution containing at least 1% by weight of an alkali metal chlorocyanurate and having a pH in the range of -7, transferring the treated fibres to a residence zone, where they are kept for a period of at least half a minute and thereafter treating the fibres with a dechlorinating agent.

Moreover, it has surprisingly been found that it is especially beneficial for the impregnated fibres to be exposed to the atmosphere during their time in the residence zone.

3,521,997 Patented July 28, 1970 This is conveniently arranged by passing the impregnated fibres over or through a succession of guides disposed in air between the impregnation zone and the dechlorinating zone, or by allowing the impregnated fibres to collect on a suitable support or in a suitable empty container located between these two zones.

The successful operation of the process is especially dependent upon the pH of the solution, which can be neutral but which preferably is very slightly acid, the optimum pH range being 5.5-6.5. Some wool fibres have an alkaline reaction and some acid may be required to ensure that the pH is within the desired range. Various acids can be used, although water-soluble aliphatic carboxylic acids, for example formic, acetic or lactic acid, are preferred. The pH can be adjusted simply by addition of the acids to the bath in which the fibres are to be impregnated.

The process can be applied to different forms of wool fibres, such as raw wool, combed or carded skeins, yarns, woven fabrics, knitted goods and finished articles such as blankets and clothing. The material to be treated can consist wholly of wool fibres or blends of wool fibres with other natural or synthetic fibrous or filamentary materials. In general, however, the material should contain at least by weight of Wool fibres.

Various alkali metal chlorocyanurates can be used, for example, potassium and sodium salts of dichloroisocyanuric acid. Very satisfactory results have been obtained by using sodium dichloroisocyanurate which is sold under the tradename Ficlor 60S, BASOLAN DC and ORCED. The amount of the chlorocyanurate which is required depends on the amount of solution applied to the fibres but is not less than 1% by weight of the solution and can be as high as 12%. For example, if the fibres are to be treated with by weight of the solution the latter preferably contains 612% by weight of the chlorocyanurate. If however, greater quantities of the solution are to be applied, then the concentration of the chlorocyanurate can be correspondingly less. Thus, if the fabrics are to be treated with 100% by weight of the solution the latter preferably contains from 3-6% by Weight of the chlorocyanurate.

The solution can be applied to the fibres in any convenient way, for example it can be sprayed onto the fibres or the latter can be passed through a bath containing the solution. Especially good results have been obtained by impregnating the fibres as rapidly as possible, notably within about 10 seconds, by immersing them in a bath of the solution containing both the salt and a wetting agent and thereafter expressing a proportion of the solution from the fibres so as to leave from 25 to 200% by Weight of the solution on the fibres. A very satisfactory method of application uses a padding technique in which the pressure on the pad rollers is preferably adjusted to leave on the fibres between 50 and by weight of the treating solution. The solution of the chlorocyanurate can be applied at ambient or elevated temperatures, preferably at l535 C. and especially at 20-25" C.

The solution can contain other ingredients. A wetting agent is preferably included, and should be compatible with the chlorocyanurate. Especially good results have been obtained with non-ionic wetting agents. The amount of wetting agent used is generally small, for example 0.2- 0.8% and preferably from DA-0.5% by weight of the solution.

The fibres are preferably kept in the residence zone for a predetermined period of between /2 and 4 minutes, during which time the reaction between the chlorocyanurate and the fibres proceeds. The residence zone can be merely the region between the impregnating zone and the vessel containing the dechlorinating agent, provided it is large enough to ensure that the treated fibres remain in it for the desired time. In practice it is preferable to provide apparatus such as a separate container, or a festoon or slide attached to a padding machine, where the treated fibres can accumulate and remain in contact with the air for the required time before dechlorination is effected.

The accompanying drawing illustrates a side elevational view of a simple form of equipment in which the present process can be carried out.

In this equipment three stainless steel bowls 1, 2, and 3 are provided respectively with pairs of guide rollers 4, 5, and 6 and adjustable mangle nips 7, 8, and 9. The first bowl contains just sufficient of the chlorocyanurate solution to cover the pair of guide rollers 4, so that the material to be treated is in contact with the liquid for as short a time as possible, preferably for not more than 10 seconds. The second bowl 2 is empty and constitutes the residence zone and bowl 3 contains a dechlorinating liquid. The relative speeds of the pairs of rollers 7, 8, and 9 can be adjusted so that the treated material can be allowed to accumulate and to remain for the desired period in bowl 2 before it is withdrawn and discharged into the bowl containing the dechlorinating liquid, which is preferably an aqueous solution of an alkali metal sulphite or bisulphite or a mixture of both, or a solution of hydrogen perioxide. This solution deactives any chlorocyanurate remaining on the fibres and improves the colour of the treated material.

This invention is illustrated by the following examples:

EXAMPLE 1 W001 fibres of 64s quality in sliver form were treated in the padding machine shown in FIG. 1 with an aqueous solution containing 4% by weight of Ficlor 60S and 0.5 by weight of a trimethylnonanol ethoxylate nonionic wetting agent (Tergitol TMN), The pH and the temperature of the solution were respectively 6.4 and 18 C., and the fibres retained 100% of their own weight of the solution, which is equivalent to 4% Ficlor on the weight of the fibres. The speed of the rollers 7, 8, and 9 was varied to give different residence periods in the empty second bowl before dechlorination in an aqueous solution containing by weight of sodium bisulphite at 50 C. The treated sliver was then withdrawn from the dechlorinating bath and rinsed thoroughly.

A piece of the treated sliver of known length was wrapped in cheese cloth and vigorously washed in a mechanical washing machine for periods of 30 and 60 minutes, after which it was removed and dried, and the reduction in length determined and expressed as a percentage of the original length. For purposes of comparison a similar test was carried out on untreated sliver.

The following results were obtained:

The negative value indicates an increase in dimension. These results show that even after 60 seconds contact with a concentrated solution of Ficlor 608, wool fibres have acquired a high resistance to shrinking. Furthermore the fibres possessed an excellent handle and colour.

EXAMPLE 2 Lengths of two different fabrics, having cover factors (C.F.) of 1.0 and 1.2 respectively and knitted from yarns consisting wholly of wool fibres of 64s quality, were treated in the padding machine shown in FIG. 1 with an aqueous solution containing 4.0% by Weight of Ficlor 605. The pH and the temperature of the solution were 4 respectively 6.4 and 18 C., and each of the lengths retained by weight of the solution. Each length of fabric remained in the second bowl for a period of 30 seconds to allow further reaction to take place, where after it passed into the dechlorinating liquid consisting of an aqueous solution containing 2% by weight of sodium sulphite and 3% by weight of sodium bisulphite at 45 C. Treated and untreated fabric were subjected to the same washing test as in Example 1, shrinkage being expressed as a percentage reduction in area.

The following results were obtained:

Hand knitting yarn was treated by passing the yarn through the padding machine shown in FIG. 1 to take up 70% by weight of an aqueous solution of 5% by Weight of Ficlor 608. The pH and temperature of the solution were respectively 6.4 and 18 C. After a residence time of 60 seconds in the second bowl the treated wool was passed into a dechlorinating bath containing an aqueous solution of 5% by weight sodium bisulphite at 45 C. The wool was then rinsed, dried and knitted into a 1 X l rib fabric having a cover factor of 0.8. The fabric was then washed for one hour in a domestic washing machine and was found to have suffered a reduction in area of 4.0%. A similar piece of fabric which had not been treated with Ficlor was reduced in area by 45% when subjected to the same washing test.

EXAMPLE 4 An aqueous solution of 4% sodium dichloroisocyanurate by weight was made containing 0.5% by weight TERGITOL TMN, a trimethylnonanol ethoxylate nonionic wetting agent. 50 kg. of 64s quality wool top slivers were padded through the solution and the squeeze roller pressure adjusted so that the fibres retained their own weight of solution. The solution was at ambient temperature (approximately 20 C.) and had a pH of 6.5.

After padding, the slivers were fed into the top of an inclined curved slide and allowed to move down the slide, the lower end of which was situated next to the following treatment tank. The slivers remained on the slide for 2 minutes before they passed through three baths of a standard industrial backwash machine, containing respectively:

Bath 1-40 g./l. sodium bisulphite at 45 C. Bath 2Water at 45 C. Bath 3--Water at 45 C.

Percent length shrinkage Washing time, Washing time, 30 minutes 60 minutes Untreated 24 31 Treated 0 1. 6

The treated material was found to have an excellent handle, and the colour was substantially better than that of wool which had been treated by conventional shrinkresist processes using dichloroisocyanuric acid or salts.

EXAMPLE 50 kg. of 64s quality wool top sliver treated by the method of Example 4, except that the three backwash baths contained the following:

Bath 1Water at 40 C. Bath 2Water at 40 C. Bath 3-3-volumes hydrogen peroxide at C.

After drying and gilling the slivers were whiter than the untreated wool and possessed an excellent handle.

Shrinkage tests on samples of the slivers gave the following results:

Percent length shrinkage Washing time, Washing time, 30 minutes 60 minutes Untreated Treated 0. 5 1. 5

EXAMPLE 6 50 kg. of 64s quality dry combed wool top slivers were treated as in Example 4, except that the three backwash baths were made up as follows:

Bath 130 g./l. sodium bisulphite at 45 C. Bath 2Water at 45 C. Bath 3- /2 -volume hydrogen peroxide at 20 C.

Untreated Treated EXAMPLE 7 100 kg. of 64s quality which was found to have an alkaline reaction was treated in a manner similar to that described in Example 6, except that the pH of the Ficlor 60S solution was adjusted to 5.8 by the addition of acetic acid. Shrinkage tests carried out on samples of treated and untreated slivers gave the following results:

Percent length shrinkage, minutes 1. A process for increasing the shrink resistance of wool fibres consisting essentially of continuously passing wool fibres into an impregnation zone and impregnating the fibres with an aqueous solution at 15-35 C. containing at least 1% by weight of an alkali metal chlorocyanurate at "a pH of 5-7; continuously transferring the impregnated fibres into a residence zone and maintaining the fibres in the residence zone in contact with atmospheric air for a predetermined period of time between 0.5-4.0 minutes; and treating the fibres with an aqueous solution containing an alkali metal sulfite or bisulfite, or hydrogen peroxide.

2. A process according to claim 1 wherein the chlorocyanurate-containing solution contains from 3-6% by weight of alkali metal chlorocyanurate.

3. A process according to claim 2 wherein the alkali metal chlorocyanurate is sodium dichloroisocyanurate.

4. A process according to claim 1 wherein impregna tion of the fibres is completed in not more than 10 seconds.

5. A process according to claim 1 wherein the fibres are in the form of a sliver.

6. A process according to claim 1 wherein the fibres are in the form of fabric.

References Cited B. R. Easton and R. F. Villiers: Continuous Open- Width Shrink-Resisting Wool Piece Goods With Sodium Dichloroisocyanurate, American Dyestufi Reporter, July 1, 1968, Pp- 523-528.

DONALD LEVY, Primary Examiner J. R. MILLER, Assistant Examiner U.S. Cl. X.R. 

